Selector



May 7, 1929. F. MERK 1,712,393

- SELECTOR I Filed July 23, 1927 4 Sheets-Sheet 1 l a l E J IIIHHIIHIIHIIIIII'U May 7, 1929.

F. MERK SELECTOR 4 Sheets-Sheet Filed July-Q25, 1927 May 7, 1929.

llllllll llllllll llllllll lllll llllllll lllllllll "Ill"! llllllll Illlllll lllll llllllll llll lll I I'll Illlllll lllllllll llllllll llllllll "llll ll llllll ll Illlll ll Illlll Illlllll Illlll Hllllll Illll lll llllll l llllllll Hllllll F. MERK SELECTOR Filed July 23, 1927 ll IHIII ll llllll llllllll HIII IHHII lllllll 'lllllll llllllll Hl llll ll llllllll lllllll I llllllll lllllll llllllll Illlllll lllllll Ullllll Illlllll ll llll Illlllll llllIHl llllll lHlllll IIHIIII lllllll llllllll ll lllll "III" "II!" llllllll Illllll lllllll III "II lllllll IIHIII III IIIHIII ll llllll llllllll IIHHIII lllllll ll, IIIIH I IIIIIIH lllllll llllllll llllllll "Ill" lllllll llllll llll lll llllllll "ll l" llllllll Illlll lllllll Ill ll llllllll lllllllll llllllll llllllll lllllll llllllll llllllll HIHI" IIIIIIH IHIIIII 4 Sheets-Sheet 3 lllll llllll lllllllll llllllll lllllll ll llll llllll lllll l Illllllll ll llllllll IIHIIII Illlllll lllllll "III" III llllll IIIIIIIII Illll ll lllllll' lllll lll Illlllll Hllllll "Ill" lllllll Ill llllll l lllllll llllllll llllll" llllllll "III" III "III "II" I IIH llll Hllll I III IHIH Hllll lllllll Illll lllll llllll "I!" I'll! lllll lllll l llll llll l I "H II III! II I! III II llll I III llll II III I II May 1,1929. j F, MERK 1,712,393

SELECTOR Filed July 23, 1927 4 Sheets-Sheet 4 Patented May 7, 1929.

PATENT OFFICE.

FRIEDRICH MERK, OE MUNICH, GERMANY.

SELECTOR.

Application filed July 23, 1927, Serial No. 208,002, and in Germany July 30, 1926.

This invention relates in general to selecto-rs for electrical switching systems and more particularly to selectors adapted for the selection or groups of bank contacts or lines (or trunks) and individual contacts or lines in a selected group. The novel selector may be .used in automatic or semi-auto matic switching systems as for example in telephone exchanges. The object of the invention is to simplify the construction oi such selectors by employing the same kind of setting operation and the some setting member for the selection of the group as well as for the selection of an individual point in a selected group.

It has been proposed to employ, in a selecior switch, a simple rotary motion or straight motion of the setting, or selecting nember instead oi the two coordinate motions as employed for example in the Strowo'er switch in the form of vertical and rotary motions. But these prior selectors give only a partial solution of the problem for, as proven by the known long-step short-step switches, although the setting; motion is uni directional, a duplicate driving mechanism cannot be dispensed with. This considerable drawback is completely removed by the present invention in which the setting; of the movable contacts of the selector for both selecting operations (group and individual) is effected by shif ing setting member in a single direction iii steps equal lon by a single driving means whose dr mg member performs successive propelling beats as in a stepping mechanism. ihc same driving means may also be used for the restoration oi the selector to normal, so that the number oi" driving means for ell'ectthe selection of groups and individual points and for restoring the selector or switch to normal is reduced to one.

The invention is illustrated by way of example in the drawing which shows 100 point selectors provided with a flat contact bank.

l is a diagrammatic representation hat illustrates the relative arr-increments or positions oi the brush carrier, brush-tripping member and the contact bank section of an individual selector.

l 2 to show the details oi the brush carrier and its brushes as viewed from the front, side and rear respectively.

l bilS Figs. 5 to 7 show a set of movable contacts or brushes in its tripped and untripped positions.

Figs. 8 to 10 illustrate the driving mechanism oi a brush carrier.

Fig. 11 is an elevation of a contact bank and a number of complete selectors arranged side by side on the bank.

Fig. 12 is a vertical section of Fig. 11.

Figs. 13 and 14 show two different kinds of brush carrier guiccs and Fig. 15 is an end or lateral fragmentary view of a horizontal strip or section of the contact bank.

The invention has been shown in the drawings as embodied in a selector or switch of the type known as a panel selector, and in the particular example shown, each selector is capable of making a connection with any one of hundred incoming or outgoing lines and these hundred lines are connected with sets of contacts each comprising, three con tacts as is well known in the art, ten of these sets of contacts t 11in a group, whereas the whole contact bank of the selector comprises ten of such groups of 10 sets of contacts. As may be best seen from Fig. 11, these ten groups, designated in the drawings by the reference numbers 110, are preferably arranged one above the other and equally spaced "from each other. The three contacts of each set oi contacts are desigated by the reference letters a, I), 0 (see A JQ'S. 2 and 11). The contacts at, Z), 0 torm vertical rows in the contact banks as clearly shown in Fig. 11.

Cooperating with these fixed groups of sets of contacts of this well known arrangement are movable contacts or wipers, preterably in the form of resilient springs, which may be called brushes, for the sake of simplicity. A movable set oi? brushes compristhe contact springs a, b, 0 0 is allotted to each group of bank contacts, the brushes a and b coope sting with the vertical rows of bank contacts a, Z), respectively, whereas the brushes 0,, 0,, of each. set cooperate with the row of bank contacts 0', which arranged in the space or gap between these brushes and may be engaged by them on both sides. These brushes 0,, 0 being electrically connected with each other may be regarded as a single contact member.

t will be understood from what has been stated above that the selector having ten groups of bank contacts comprises ten sets of brushes (in, Z), 0,, 0

11 is a movable brush-carrier for these ten sets 01 brushes comprising three bars 12, 13 and 14 insulated from each other and held together in proper relation by clamping screws 42, insulating Washers 45 and spacing members 46 respectively. The ten brushes a are clamped directly to the atorcsaid bar 12 by means of the screws 42, and in the same manner the brushes 5, c, and 0 are clamped on to the bars 14 and 13 respcctively. By their contact with the bars 12, 13, and 1 1, the corresponding brushes of the different sets are electrically connect ed in parallel or, in other words, all brushes a are in a so-called multiple connection with each other, and the same applies to the brushes b as well as to the brushes 0,, 0 The ten sets of brushes are preferably arranged upon the carrier 11 at equal distances apart, which distances however are different from and smaller than those of the groups of bank contacts, as will be more fully described later on.

The springs or brushes a, b, 0,, c, are set in such a manner that they all tend to approach their respective row of cooperating fixed contacts a, b, 0. Each set of brushes cooperates with a spring member 16 provided with two projections 15 and a horizontally bent tongue 17 having a front edge 20 and fixed to the brush carrier 11. The outer brushes (1 and I) rest upon insulating members or projections 33 attached to the inner brushes 0,, a The latter rest in turn against the projections 15 (Fig. 6). The internal stress of the spring 16 forming a brushtripper is arranged to urge it against the back of the middleQiar 13 (Fig. 5). The horizontally bent tongue 17 of the spring 16, which has a perforation or aperture 18 (Fig. 5) embraces the middle bar 13 and is thus held in its correct position against the lat eral pressure exerted by the brush. springs. At a position slightly to the rear of the projections 15, the brushes 0,, 0 each have a small hole 19 (Fig. 7).

l/Vhen the brush-trippcr 16 is struck or temporarily pressed backwards by a light blow dealt against its forwardly projecting end 20 by a device which will be described below, the two projections 15 register with the holes 19 and all the brushes (1 b, 6,, c 01 the set then immediately assume their ellective or bank-contact wiping position as shown by the bottom brush set illustrated in Figs. 2 and 4, whereas the upper sets of brushes have been shown in these figures in their normal or untripped position. The distance between the free ends or edges 20 of the brush trippers 16 cooperating with the brushes is equal to that of the corresponding sets of brushes.

The bars 12, 13 and 14: oil the carrier 11 are rather thin and consist of light metal and the brushes (1, Z), 0,, c, and their trippers 16 are made of thin [lat springs. so that the brush carrier with its attached members is a very light unit compared with the brush carriers of previously proposed switches. Furthermore, the bars and brushes are placed edgcwise. relati\- cl v to the face of the contact bank so that the latter is not obscured to an observer by the parts arranged before it.

A driving mechanism .tor imparting a step-by-step movement of the brush carrier 11 and its attached members has been shown in Figs. 8 to 10. This driving mechanism comprises a stepping electro-magnet 21 arranged on a frame plate 37 and a rack or ratchet bar 24- guided between two guide rods 22, 23. The electro-magnet 21 is actuated in a manner described later on by series of electrical impulses to selecta bank contact group and an individual set of contacts in this group as well as for restoring the brushes of the brush carrier 11 to their normal position of rest by steps of equal length, and when actuated by impulses it acts upon the ratchet bar 24 by means of a pawl 38 pivotably connected with the armature 47 of the magnet. A retaining or holding pawl 39 engages the bar 2 1.

The brush carrier and the driving mechanism are constructed in two separate units that are only connected when they are placed in the selector in their working positions.

The operative connection between these units is effected by an insulated coupling member 25 provided with a n'ojcction 26 (F ig. adapted to be received in a slot 27 or the like in the ratchet bar.

Guide bars 35 have been arranged in front of and parallel to the vertical rows of bank contacts a, Z), c for guiding the brush carriers 11 in their moven'ient when pushed forward by the eleetro-magnet 21 or when returning to zero position upon retracting ot the pawls 38 and 39 from the bar 24, and these bars may be united to form a plurality o1" selectors arranged side by side in a unitary grid-like structure as shown in Fig. 13. In a preferred form, however, each pair oi bars 35 tor guiding one brush carrier 11 and its cooperating parts has been connected to a rectangular rame 36 as shown in elevation side view and plan view by F ig. 14. Any suitable fastening means, such as hooks 43, screws (not shown) and the like, may be provided to reinovably connect the frame member 36 in position at the main frame 48 of the selector. Projecting arms 28 (Fig. 2) attached to the brush carrier 11 at suit able distances apart are shaped so as to embrace and cooperate with the guiding bars 35, so that the brush carrier 11 will be guided in a vertical direction in front of the bank supported but held against longitudinal movement preferably within the frame 36 and has ten attached strikers 3 (Figs. 1 and 14), one for each group of bank contacts 110 and their corresponding sets of brushes respectively and adapted to cooperate with the edges 20 of the brush tripperz-i 16. The distances between the strikers 34 are the same as the distances between the said groups of bank contacts. There is one striker for each set of brushes.

On the other hand, the sets of brushes a, b, 0,, 0 are fixed upon their carrier 11 in such a manner that when the brush carrier 11 is in its normal position (as shown in Fig. 1), the distance :0 to 00 of the brush tripper edges 20 from their cooperating arm or striker 34 near the lower end of the cooperating bank contact groups differ from group to group by one step length. Preferably the length 92 will be equal to the length of one step of the brush carrier.

At one end of the bar 32 of the brush-releasing device, the armature tt of a magnet 30 is fixed (see Fig. 11) in such a manner that upon actuation of the magnet 30 and attraction of the armature 14, the bar 32 is rotated about its longitudinal axis for a small angle in such'a manner that the arms 3 1- attached to the rod 32 are swung in a horizontal direction and approach the bank of contacts. 'On account of the difference of distances 00 to upon actuation of the magnet 30, only one of the said arms can encounter the edge 20 of one brush tripper 16. whereas the edges of the other brush trippers are not in alinement with the corresponding arms. It will be understood that the lowermost edge 20 will be struck by its cooperating arm or striker 3 1 when the magnet 30 isactuated after the brush carrier 11 has been shifted one step by the magnet 21, whereas the second edge 20 is struck when the actuation of the magnet 30 follows a shifting of the carrier for two steps, etc.

The special brush tripper 16, which is operated on by the blow of the striker 34 is moved from the position shown at the top of F 3 into the position shown in the middle part of the figure, and by this operation, the corresponding brushes a, Z), 0,, 0 are influenced as described above, so as to assume their effective bank-contact wiping position. The respective arrangement of parts is so chosen that the tips of the brushes brought into their contact wiping position ar: always a distance of one step below the lowermost or first set of contacts of their respective group of bank contacts. In other words, the tips of the lowermost sets of brushes are, in their position of rest, two steps below (or before) the first cooperating of contacts and so on, the distance between the uppermost sets of brushes and the first row of the uppermost group of bank contacts being 12 steps.

Arranged beyond or above the uppermost row of fixed contacts of each group 1-1O and preferably one step above the uppermostcontact of the series 0 is a fixed separating or spreading member 29 adapted to be encountered by the tips of the brushes 0,, 0 when these have been shifted forward beyond their ccopcrating group of bank contacts. The members 29 are broader in the horizontal direction than the contacts 0' (see Fig. 15) and when the brush tips of a brush and set unspread by the actuation of the brush-tripper 16 ride over the member 29, they are spread or forced further apart. Thereupon the projections 15 of the brush tri; 16 are no longer retained by the holes the spr ngs 0,. c and the released ,Lu (,1 brush tripper 16 is allowed to return again to its normal position with its projections 15 between the uninterrupted parts of the brushes 0,, c, as shown in Figs, 6 and 7. When the tips of these brushes leave the spreading member 29, the brushes come again in contact with and are held in their spread position by the said projections 15.

As to the manner of operation of the selector switch desci ibed above, it is to be understood that as it is well known to persons skilled in the art, selectors having bank contacts of 100 sets of contacts are ordinarily adjusted by two series of impulses of 1 to 10 in'ipulses, one impulse series for the tens or groups of the contacts and the other for the units. As is also well known, each series of impulses is followed by one single switch-over or controlling impulse received by a special controlling magnet. As the means for creating the said impulses and carrying them to the respective magnets are not in any way the subject matter of the present invention, it is not necessary to show such apparatus and circuits. It may be understood howev that the two series of impulses for selection referred to above are transmitted to the actuating magnet 21, whereas the switch-over impulse sent between the two impulse series is transmitted to the magnet 30.

it may be assumed that this switch is to be adjusted to the contact set N0. 28, which means the third row of contacts in the second contact group. F or bringing about the adjustment, the magnet 21 is to be energized twice (by a series 01 two impulses) then a controlling impulse is imparted to the magnet 30, whereupon a second series of three impulses is transmitted again to the magnet 21.

The two impulses sent to the magnet 21 at first cause it to shift the brush carrier 11 upwardly for two steps. After these two steps of the brush carrier the tips of the second set of brushes are standing ust one step before the second group 2 of bank con tacts a c, and in this position the striker 3st of the rod 32 attributed to the second group of contacts, is just in front of or in alignment with the front edge 20 of the brush tripper 16 of the second set of brushes. The switching-0v r impulse now imparted to the magnet 80 rotates the bar 32 v "h arms 341, the second of which. strik s against the edge 20 ot' the second brush tripper 16 and pushes it backwards, so that the projections 15 enter the holes 19 and the brushes (1, b, 0,, c of the second set are allowed to move inwardly into their etliective position as referred to above.

lVhen now the second series of impulses aetuates the magnet 21, then the set of brushes which has been made effective contacts after the first step with the first step of contacts in the selected second group ot bank contacts, and after the third step the brushes engage the third ot the said contacts, it being understood that there is no lost motion or step at all for the brushes in their advancing movement as in all prior constructions.

lVhen the considered selector, and as well known in the art, further cooperating selectors in larger exchanges have been suitably adjusted, the conversation between the calling and the called subscribers goes on in the usual way. When the conversation is over, the stepping magnet 21 is connected in a known manner to an impulse sender in the oflice sending out any desired number of impulses and when connected in this manner, the brush carrier 11 is switched upwards in the same direction as before.

A fter a number of steps when the etfective or tripped brushes have passed their cooperating group of bank contacts, the brushes 0,, c encounter and are spread by the spreading member 29, and the brush tripper 16 is allowed to return to its normal position between the springs 0 This spreading action takes place when the brush carrier has stepped forward up to the end of its upward movement; at the same time the pawls 3S and 39 cooperating with the rack 24 are in a well known manner retra ted from the rack (by means not shown .in the drawings), whereupon the brush carrier freely returns into its lowermost position of rest. It will be clear that during this return movement, no brush of the ten sets of brushes contacts with the bank conta as all the brushes are in their spread and inoperative position ot' rest. The selector is then again available for further operation.

In the above-described selector all the lost motions that happen in known panel type selectors between the operations of selecting a group and a point in the roup. and which owe their existence to thcr register control feature, are completely avoided. Every step executed a selecting step, i. e. every step taken efl ects the selection ot a group or a point in a group, even though all the steps are executed in the same direction and are of equal lengths. This feature ot the invention is obtained by the above delined displacement of the brushes on their brush carrier in their direction of travel relative] y to their bank contact groups. By arranging this displacen'ient in such a manner that by the last step of the group selecting stepping operation the proper brush set is moved to a point which is one step from the desired group, and by tripping the brush set at this point, the next step can be arranged to be a unit's selecting step or one ot the steps that sets the brushes onto the desired individual line.

The massive complicated brush arrangencnt which, in'hnownselectors ot the panel ype, covers the contact bank is substituted n my novel panel by a light, simple, small brush mechanism that enables all parts of 'he selector to be easily inspected.

The light weight of my novel. step-by-stcp selectors which are controlled directly from the calling stations constitutes a great improvement compared with the known electromotor-driven panel type switches which are controlled with the aid of impulse-storing registers.

For the operations of selecting the desired group and a wanted point in the group, only a single drive (stepping electronn'ignet or a pneumatic hammer drive or the like) is employed and this drive may also be used to effect the restoration of the selector to normal if the restoring members are arranged to be operated by the progression of the brush carrier to the end of their travel. Consequently the arrangement of the driving mechanism of the selector is the most simple imaginable.

The scope of the invention not limited to the construction shown herein in which a common brush carrier and brush-relcasing members with invariable operating positions are en'iployed. Other arrangements may be included in the scope ot the claims as for example an arrangement in which the tripping of the proper set of brushes is effected by :a member that slides in the brush carrier, or arrangements in which the single drivingmechanism first produces a rotary motion to select the proper set of brushes and then causes the brush carrier to rise. The invention includes within its scope all arrangements in which asingle driving means moves a setting member step-by-step in steps of equal lengths in the same direction both for the selection of the desired group and any desired point in that group.

Another advantage of the invent-ion is that it enables any form of contact bank to be adopted. Although the use of one setting device for a panel type switch forms the starting point from which the invention was developed, the definition of the same (displacement of the brush sets relatively to their contact bank sections) is such that structures may be included in its scope irrespectively of the arrangement of their rows of bank contacts, i. e. these rows may be straight or circular and in either case they be behind or (beside each other. The invention therefore enables the most advantageous form "of contact bank to be used and this, at the present time, is the flat bank which requires no cabling or soldering and permits of the arrangement of selectors at the front and back of the bank.

1. In a'selector comprising groups of bank contacts, a plurality of sets of movable brushes, one for each of the said groups, means for rendering anyone of said sets of brushes effective to cooperate with its group of bank contacts, a common carrier for the said sets of brushes, and a driving mechaism for shifting the said carrier in one direction and in steps of equal length, the arrangement of the brushes upon the carrier being such that, when the carrier is in its normal position, the distance of each brush set from its group of contacts differs by the .length of one step of said driving mechanism from the distance between another brush set and its bank contact group.

2. In a selector comprising groups of contacts, a plurality of sets of movable brushes, one for each of the said groups, tripping means having one actuating memher for each set of brushes for rendering any particular one of the said sets of brushes effective to cooperate with its group of bank contacts, a common carrier for the said sets of brushes, a driving mechanism for causing a relative step-by-step movement between the said sets of brushes and the said actuating member such that for each of a certain number of steps, one single set of brushes spaced one step from its group of contacts and its actuating member are brought into alignment, and means for making effective the said actuating member so as to trip the said set of brushes to cooperate with its group of contacts.

3. Ina selector comprising groups of bank contacts, a plurality of movable brush sets, one for each of the said contact groups, brush tripping members, one for each of the brush sets and adapted to trip its set of brushes instantaneously just before- :the set of brushes engages its group of bank contacts, a common carrier for the brush sets and their tripping members, and a driving mechanism for shifting the said carrier in one direction and in steps of equal length, the distances between the brush sets and groups of bank contacts respectively being so chosen that only a single one of them at a time is shifted into operative position just before engaging its bank contact group.

t. In a selector comprising groups of bank contacts arranged in spaced relation, a set-of brushes corresponding to each group of contaets, brush tripping members, one for each of thesaid brush sets and being spaced apart less than the distances of the corresponding groups of bank contacts, a common carrier for the brush sets, and a brush releasing member common to all said sets of brushes provided with a plurality of actuating members, one for each of the said brush tripping members and arranged on said brush releasing member at the same spacing as the groups of bank contacts, said brush releasing members being adapted to cause only one of the brush tripping members to trip its set of brushes after a group selecting movementof' the brush carrier for av certain number of steps.

5. In a selector comprising groups of bank contacts, a common brush carrier with sets of brushes, one for each of said bank contact groups, means for moving the said brush carrier with respect to the said bank contacts in steps of equal length, the distances of the said sets of brushes from their respective groups of bank contacts difiering from group to group by the length of one step, means for controlling the step-by-step movement of the said carrier so as to deliberately bring each one of the said brush sets into a position at a distance of one stop be fore its respective group of bank contacts, brush tripping members, one for each of the said brush sets and arranged in a fixed relation to their respective brush sets and being fixed on to the said brush carriers, a rotary brush-releasing rod common to all said brush sets and having a plurality of striking arms, one for each of said sets, and means for turning said rod to actuate one of the said tripping members by means of one of its strikin arms so as to release that brush set which nas been shifted into a position one steps length before its group of bank contacts.

In a selector comprising groups of bank contacts, a common brush carrier with brush sets, one for each group of bank contacts, means for rendering any one of said sets of brushes effective to cooperate with its group of bank contacts, a single driving mechanism for shifting said brush carrier in one direction and in steps of equal length both to select a group of bank contacts and to select a contact in the selected group, the said groups of bank contacts on the one hand and the said sets of brushes on the other hand being arranged in such a manner that the number of steps'necessary to bring one of the said sets of brushes into a position just before its group, of bank contacts differs from one set to another.

7 In a selector comprising groups of bank contacts, a common brush carrier with brush sets, one for each bank contact group, means for rendering any one of said brush sets effective to cooperate with its group of bank contacts, means for restoring said brush sets, a single driving mechanism for shifting said brush sets in one direction and in steps of equal length firstly to select a group of bank contacts, secondly to select a contact in the selected group and thirdly to a brush restoring position, and means to return the brush carrier into its normal position after the said restoring means have become operative.

8. In a selector, a movable brush carrier, contact brushes mounted on either side of said carrier and provided with apertures, and a brush-tripping member normally ongaging the brushes but adapted when actuated to project into said apertures and permit the brushes to move to a desired position.

9. In a selector, a movable brush carrier, resilient contact brushes secured at one end to the brush carrier, the free ends of the brushes being movable in a common plane, and a resilient tripping member secured at one end to the brush carrier and provided with portions normally engaging the brushes, the free end of the trpping member being movable in a plane at right angles to the plane of movement of the free ends of the brushes to disengage the same from the brushes.

10. In a selector, a movable brush carrier, a group of bank contacts cooperating therewith, brushes on the brush carrier normally held in inoperative position, means for tripping the brushes to permit engagement with the bank contacts and means at the end of the group of bank contacts forrcturning the brushes to inoperative position.

11. In a selector, a movable brush carrier, comprising a frame having a plurality of parallel members and a plurality of sets of brushes supported on said brush carrier, the corresponding brushes of each set being electrically connected in multiple by the said frame members of the carrier.

12. In a selector, a vertical contact bank compris'sin a plurality of groups of contacts arranged to form a flat panel, a. movable brush carrier supported in front of said contact bank and a plurality of sets of brushes supported on said brush carrier, one set of brushes for each group of bank contacts, said brush carrier embodying thin frame members disposed edgewise with respect to the contact bank so as to facilitate inspection of the bank contacts.

In testimony whereot I have affixed my signature.

FRIEDRICH M ERK. 

